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lighting for HD


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#1 william koon

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Posted 16 December 2006 - 05:44 AM

Is lightmeter needed for HD shooting for at least to check lighting ratio? Some suggest that they only depend on the waveform monitor to judge. How do we judge depending on the waveform? Please explain step by step how to use the waveform as a reference.
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#2 David Mullen ASC

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Posted 16 December 2006 - 12:37 PM

Is lightmeter needed for HD shooting for at least to check lighting ratio? Some suggest that they only depend on the waveform monitor to judge. How do we judge depending on the waveform? Please explain step by step how to use the waveform as a reference.


You can use a light meter to measure key-to-fil ratios... or you can see it with your own eyes on the monitor and set the level of fill by eye/monitor and skip the meter if you want.

I use a light meter more in HD when I am lighting a big space and want to make sure that the levels match, like when a person walks through a series of spots or key lights and I want them to be at f/2.8 each time they hit the light, let's say. May be quicker than doing all of that by eye/monitor.

A waveform tells you more about overall exposure and where your detail is falling -- if a lot of the information seems near the top of the waveform screen near the 100 IRE cut-off point, perhaps, you may want to stop down and lower the levels to somewhere more in the middle to keep information from clipping.
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#3 william koon

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Posted 18 December 2006 - 05:35 AM

You can use a light meter to measure key-to-fil ratios... or you can see it with your own eyes on the monitor and set the level of fill by eye/monitor and skip the meter if you want.

I use a light meter more in HD when I am lighting a big space and want to make sure that the levels match, like when a person walks through a series of spots or key lights and I want them to be at f/2.8 each time they hit the light, let's say. May be quicker than doing all of that by eye/monitor.

A waveform tells you more about overall exposure and where your detail is falling -- if a lot of the information seems near the top of the waveform screen near the 100 IRE cut-off point, perhaps, you may want to stop down and lower the levels to somewhere more in the middle to keep information from clipping.

thx David. What ASA should I use then? or shall I set to about 320 ASA just to get a guide for the key to fill ratio followed by setting of exposure by refering to monitore (assuming I have no waveform monitor)?
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#4 Francesco Bonomo

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Posted 18 December 2006 - 06:14 AM

What ASA should I use then? or shall I set to about 320 ASA just to get a guide for the key to fill ratio followed by setting of exposure by refering to monitore (assuming I have no waveform monitor)?


Different cameras=different EI (ASA) ratings.
You should test the camera before the shoot and find your own.
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#5 David Mullen ASC

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Posted 18 December 2006 - 02:09 PM

Since I'm not using my meter to set exposure on the camera, just to balance lights relative to each other, I generally use 320-400 ASA on my meter when using the F900, but that might not be close-enough for every HD model out there, especially if you are trying to light to the maximum f-stop of the lens. So you need to test, but it shouldn't take much time.

A grey card with 10 Zones, a flat key light, and the camera's zebras can give you a quick idea if you don't have a waveform monitor. Set the zebras to appear both a 70 IRE and 100 IRE; the light grey stripe just one-stop above (lighter than) the middle 18% grey stripe, which is supposedly "causasian skintone value" and the white stripe should zebra in the viewfinder when you set a certain f-stop on the lens, then play with your meter's ASA and shutter speed values (matching the shutter speed in the camera) until you get the same results with your meter. Not completely accurate, but close enough for lighting with.

It's funny though but I've learned from shooting HD that I tend to light night interiors almost a stop darker than what my meter tells me, to look natural. I guess at night, things are rarely at full key.
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#6 Bob Hayes

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Posted 18 December 2006 - 11:44 PM

I really rely on the waveform and monitor to determine the exposure. In my experience meters don?t work well determining lighting ratios or ASA because the contrast ratio, sensitivity, and Gamma on these cameras are so adjustable.
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#7 Jim Feldspar

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Posted 19 December 2006 - 02:24 PM

Since I'm not using my meter to set exposure on the camera, just to balance lights relative to each other, I generally use 320-400 ASA on my meter when using the F900, but that might not be close-enough for every HD model out there, especially if you are trying to light to the maximum f-stop of the lens. So you need to test, but it shouldn't take much time.

A grey card with 10 Zones, a flat key light, and the camera's zebras can give you a quick idea if you don't have a waveform monitor. Set the zebras to appear both a 70 IRE and 100 IRE; the light grey stripe just one-stop above (lighter than) the middle 18% grey stripe, which is supposedly "causasian skintone value" and the white stripe should zebra in the viewfinder when you set a certain f-stop on the lens, then play with your meter's ASA and shutter speed values (matching the shutter speed in the camera) until you get the same results with your meter. Not completely accurate, but close enough for lighting with.

It's funny though but I've learned from shooting HD that I tend to light night interiors almost a stop darker than what my meter tells me, to look natural. I guess at night, things are rarely at full key.


"the middle 18% grey stripe, which is supposedly "causasian skintone value" "

This is so basic a question please don't shoot me but I though that when using a meter
the stop you get is for 18% grey and then you open up 2/3 to a full stop for
caucasian skin tones or stop down 2/3 to a full stop for dark skin tones?
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#8 Mario C. Jackson

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Posted 19 December 2006 - 03:10 PM

I think it is a good idea to always use your light meter. I just finished a 50 minute movie that was shot on HD and I used my light meter every bit of the way. My meter was my safety net and it allowed me to be confident with the image especially when to monitor was not working. I usually dont trust monitors to much but that does not mean that I am right.
Hope this Helps
Mario C. Jackson
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#9 Leo Anthony Vale

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Posted 19 December 2006 - 03:36 PM

"the middle 18% grey stripe, which is supposedly "causasian skintone value" "

This is so basic a question please don't shoot me but I though that when using a meter
the stop you get is for 18% grey and then you open up 2/3 to a full stop for
caucasian skin tones or stop down 2/3 to a full stop for dark skin tones?


Back I high school I read that if one takes a reading off of one's hand, open up a stop.
Also green grass is usually 18%.
Whenever possible I metered off of grass, & opened up when metering off my hand.
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#10 David Mullen ASC

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Posted 19 December 2006 - 10:00 PM

"the middle 18% grey stripe, which is supposedly "causasian skintone value" "


You didn't quote enough of the sentence, which was:

the light grey stripe just one-stop above (lighter than) the middle 18% grey stripe, which is supposedly "causasian skintone value"

Zone 6, I guess, not Zone 5... one-stop lighter than 18% grey is traditionally "caucasian skin tone" brightness, although we know that's not really accurate. So if you use a spot meter on a white person's face, you are supposed to open-up another stop from your reading so that it will render one-stop lighter than 18% grey in reflectence.
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#11 Jim Feldspar

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Posted 20 December 2006 - 12:34 AM

You didn't quote enough of the sentence, which was:

the light grey stripe just one-stop above (lighter than) the middle 18% grey stripe, which is supposedly "causasian skintone value"

Zone 6, I guess, not Zone 5... one-stop lighter than 18% grey is traditionally "caucasian skin tone" brightness, although we know that's not really accurate. So if you use a spot meter on a white person's face, you are supposed to open-up another stop from your reading so that it will render one-stop lighter than 18% grey in reflectence.


Thanks!
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